<template>
  <div class="goods">
    <div class="menu-wrapper" ref="menuWrapper">
      <ul>
        <li v-for="(item,index) in goods" class="menu-item" :class="{'current':currentIndex===index}"
        @click="selectMenu(index,$event)">
          <span class="text border-1px">
            <span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>
            {{item.name}}
          </span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper" ref="foodsWrapper">
      <ul>
        <li v-for="item in goods" class="food-list food-list-hook">
          <h1 class="title">{{item.name}}</h1>
          <ul>
            <li @click="selectFood(food,$event)" v-for="food in item.foods" class="food-item border-1px">
              <div class="icon">
                <img width="57" height="57"  :src="food.icon">
              </div>
              <div class="content">
                <h2 class="name">{{food.name}}</h2>
                <p class="desc">{{food.description}}</p>
                <div class="extra">
                  <span class="count">月售{{food.sellCount}}份</span><span>好评率{{food.rating}}%</span>
                </div>
                <div class="price">
                  <span class="now">￥{{food.price}}</span><span
                  class="old" v-show="food.oldPrice">￥{{food.oldPrice}}</span>
                </div>
                <div class="cartcontrol-warpper">
                  <cartcontrol @add="addFood" :food="food"></cartcontrol>
                </div>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>
    <shopcart ref="shopcart" :select-foods="selectFoods" :delivery-price="seller.deliveryPrice" :min-price="seller.minPrice"></shopcart>
    <food @add="addFood" :food="selectedFood" ref="food"></food>
  </div>
</template>

<script type="text/ecmascript-6">
  import BScroll from 'better-scroll';
  import shopcart from 'components/shopcart/shopcart';
  import cartcontrol from 'components/cartcontrol/cartcontrol';
  import food from 'components/food/food';

  const ERR_OK = 0;

  export default {
    props: {
      seller: {
        type: Object
      }
    },
    data() {
      return {
        goods: [],  // 商品列表
        listHeight: [],  // 每个区域的高度
        scrollY: 0,
        selectedFood: {}
      };
    },
    computed: {
      currentIndex() {
        for (let i = 0; i < this.listHeight.length; i++) {
          let heightNow = this.listHeight[i];
          let heightNext = this.listHeight[i + 1];
          if (!heightNext || (this.scrollY >= heightNow && this.scrollY < heightNext)) {
            return i;
          }
        }
        return 0;
      },
      selectFoods() {
        let foods = [];
        // 遍历所有分类下的所有被选择的商品
        this.goods.forEach((good) => {
          good.foods.forEach((food) => {
            if (food.count) {
              foods.push(food);
            }
          });
        });
        return foods;
      }
    },
    created() {
      this.classMap = ['decrease', 'discount', 'guarantee',
        'invoice', 'special'];
      this.$http.get('api/goods').then((response) => {
        response = response.body;
        if (response.errno === ERR_OK) {
          this.goods = response.data;
          // 因vue更新dom是异步的，所以需要放在nextTick这个接口中初始化Scroll
          this.$nextTick(() => {
            this._initScroll();
            this._calculateHeight();
          });
        }
      });
    },
    methods: {
      // 选择到了第几个菜单
      selectMenu(index, event) {
        // 如果为浏览器原生点击事件,则直接返回
        if (!event._constructed) {
          return;
        }
        let foodList = this.$refs.foodsWrapper.getElementsByClassName('food-list-hook');
        // 对应的商品列表的高度
        let el = foodList[index];
        this.foodsScroll.scrollToElement(el, 300);
      },
      addFood(target) {
        this._drop(target);
      },
      // 初始化滑动窗口
      _initScroll() {
        this.menuScroll = new BScroll(this.$refs.menuWrapper, {
          click: true
        });

        this.foodsScroll = new BScroll(this.$refs.foodsWrapper, {
          click: true,  // 滚动框架不拦截点击事件
          probeType: 3  // probeType为3，将在屏幕滑动的过程中和momentum滚动动画运行过程中实时派发scroll事件
        });

        // 实时获取滚动的距离
        this.foodsScroll.on('scroll', (pos) => {
          this.scrollY = Math.abs(Math.round(pos.y));
        });
      },
      _calculateHeight() {
        // 获取每一个分类的列表
        let foodList = this.$refs.foodsWrapper.getElementsByClassName('food-list-hook');
        let height = 0;
        this.listHeight.push(height);
        // 初始化商品分类列表的高度
        for (let i = 0; i < foodList.length; i++) {
          let item = foodList[i];
          height += item.clientHeight;
          this.listHeight.push(height);
        }
      },
      selectFood(food, event) {
        // 如果为浏览器原生点击事件,则直接返回
        if (!event._constructed) {
          return;
        }
        this.selectedFood = food;
        this.$refs.food.show();
      },
      _drop(target) {
        // 体验优化，等待dom更新完成后，再触发子组件的drop方法
        this.$nextTick(() => {
          this.$refs.shopcart.drop(target);
        });
      }
    },
    components: {
      shopcart,
      cartcontrol,
      food
    }
  };
</script>

<style lang="stylus" rel="stylesheet/stylus">
  @import "../../common/stylus/mixin.styl"

  .goods
    display flex
    position absolute
    top 174px
    bottom 46px
    width 100%
    overflow hidden
    .menu-wrapper
      flex 0 0 80px
      width 80px
      background #f3f5f7
      .menu-item
        display table
        height 54px
        width 56px
        line-height 14px
        padding 0 12px
        &.current
          position relative
          z-index 10
          background #fff
          font-weight 700
          .text
            border-none()
        .icon
          display inline-block
          vertical-align top
          width 12px
          height 12px
          margin-right 2px
          background-size 12px 12px
          background-repeat no-repeat
          &.decrease
            bg-image('./imgs/decrease_3')
          &.discount
            bg-image('./imgs/discount_3')
          &.guarantee
            bg-image('./imgs/guarantee_3')
          &.invoice
            bg-image('./imgs/invoice_3')
          &.special
            bg-image('./imgs/special_3')
        .text
          display table-cell
          width 56px
          vertical-align middle
          border-1px(rgba(7, 17, 27, 0.1))
          font-size 12px
    .foods-wrapper
      flex 1
      .title
        padding-left 14px
        height 26px
        line-height 26px
        border-left 2px solid #d0dde1
        font-size 12px
        color rgb(147, 153, 159)
        background #f3f5f7
      .food-item
        display flex
        margin 18px
        padding-bottom 18px
        border-1px(rgba(7, 17, 27, 0.1))
        &:last-child
          border-none
          margin-bottom 0
        .icon
          flex 0 0 57px
          margin-right 10px
        .content
          flex 1
          .name
            margin 2px 0 8px 0
            height 14px
            line-height 14px
            font-size 14px
            color rgb(7, 17, 27)
          .desc, .extra
            line-height 10px
            font-size 10px
            color rgb(147, 153, 159)
          .desc
            line-height 12px
            margin-bottom 8px
          .extra
            .count
              margin-right 12px
          .price
            font-weight 700
            line-height 24px
            .now
              margin-right 14px
              font-size 14px
              color rgb(240, 20, 20)
            .old
              text-decoration 10px
              font-size 10px
              color rgb(147, 153, 159)
          .cartcontrol-warpper
            position absolute
            right 0
            bottom 12px
</style>
